Electrically-propelled motor-car.



P. G. LILJENROTH.

ELEGTBIOALLY PBOPELLED MOTOR GAB. APPLIOATIOH nun APLB, 1912.

1,052,263. Patented Feb.4, 1913.

UNITED STATES 1 ATENT OFFICE;

rams e. LILJENBO'I'H, or vns'rnaAs, SWEDEN,

ELEGIRICALLY-PROPELLED MOTOR-CAB.

Specification Letters Patent.-

Patented Feb. 4, 1913.

Application flied April 8, 1912. *Serial No. 889,898. v

To all whom it may concern:

Be it known that I, FRANS G. LILIEN- Born, a citizen of the Kingdom of Sweden, residing .at Yesteras, Sweden,have invented new and useful Improvements in Electrically- Propelled Motor Cars, of -which the following is a specification.

It is well known to pro motor cars by means of an internal com ustion motor inv such manner that an electric power trans mission consisting of a continuous-current generator and a continuous current motor is arranged betweenv the internal combustion motor and the wheels of the car. The advanta e of such propulsion system lies cs sentia y in that the internal combustion motor may run at constant speed and torque while 'the nece'ssa'ry variations of the speed and tractive power of the car ma be ac complishedby regulating the electric power transmission. Forthe purpose of obtaining small dimensions of the electric machines and small losses in the electric power transmission the variationsgof the torque of'the electric motor should be controlledin such manner that the voltage and the intensity 1 of the'electric main current vary as little as a possible. a

The object of, the

. invention is to obtamsuch an elfect y exciting the field of the electric motor in such manner, that great variations of the field strength of the motor are affected when the intensity of the main current varies slightly.

The invention consists, chiefly, inthe combination with an electric wer transmitting system for 'electricall propelled cars, ofan exciter for the driving motor having three field windingsflone of which .is

shunted to the armature of the generator, and the second of which is connected in series to the armatures of the generator and the driving motor and so arranged that it counteracts thefirstmentioned winding, while the third winding is connected to tho armatureof the exciter itself;

In the accompanying drawing I have car.- The motor M s an with two magnetizing windin F and F, respectively. Thewiriding ries to the armature of the motor M. The winding F is connected to'the armature of an exciter E, which may be driven by the internal combustion engine D directly or by means of any: suitable transmission not shown in the drawings. The exciter, E has three field windings L, L, and L respec- F, is connected in se-' tively. The winding L is shunted to the I armature of the generator G and its circuit may contain a suitable; rheostat R. The winding L is connected in series as the armatures of the, generator G and the motor M in such manner that it counterac s the winding L vThe winding L is shunted to the armature of the exc'it'er itself, but na be connected in series thereto, "if. deslr The winding L has such a large resistance -that the machine .cannot exeite. itse1f -b means-of said winding alone? The wm .ings L and L, are so proportioned in relation to eachother that'they 'atinormal voltage and intensity of the current delivered by the generator'G compensate each other, the voltage of the exciterE being accordly nil under such circumstances.

he operation of the system above described is as follows: If the resistance to,

the propulsion of the car begins to increase over the normal value, the car has a tendency to decrease its speed, the intensity of the main current bemg-as a consequence increased. The winding L, accordingly preponderates over the winding L', and ex cites the machine E so that the latter delivers a magnetizin ing F of the motor The winding F is connected to the armature of the exciter E in such manner that in this case the field of the motor M is stre hened; The torque of the motoris' accor ingl'y increased andits speed; decreases while its watts'remam substantially constant. If on "the other hand the resistance to the propulsion of the car decreases under--its normal value, the winding L will preponderate over the winding L and the excitation of. the machine E will be'reversed. The exciter IE- will accordingly in such case deliver a ma netizing current to the winding F whic weakens the magnetization of the motor M so that the torque of the latter will decrease and its speed increase, the watts of the motorl always remaining substantially concurrent to the windj stant. Inasmuch as the exciter E on account of the provision of the three field windings L -,L is very sensitive for variations of the intensity of the main current, great variati'ogs of the field strength of the motor M are? obtained at small variations of the intensity ofithe main current. Great variations of the speed and torque of the motor mayaccordingly be obtained automatically while the intensity as well. as the voltage of the current remain practically constant. As the voltage andcurrent intensity of the generator vary only slightly, the dimensions of said machine need not be taken larger than what corresponds to the watts actually transmitted. I

By adjusting the rheostat R one may vary the value of the intensity and' voltage Ojfthemain current at which the windings L and'L compensate each other and in such manner control the amount of the power-transmitted; The. internal combustion engine must in such. case, ofcourse, be provided with a suitable regulator so that its effect mayvary in a corresponding man- In the modification shown in Fig. 2 the driving motor has only one magnetizing winding F which .is connected in series to the armatures' of the generator G and the motor M, while the armature of. the'exciter. E is connected inparallel to said winding F. In other respects the arrangement is the same as in Fig. 1. I

.The modification shown in Fig. 3 diflers from that shown in Fig. 1 only by that the field winding F of the motor M is shunted I to the armature of the motor.

In the modification shown in Fig. 4 the motor M has only one field winding F which is in series'to the armature of the exciter E connected to. the armature of the -motor M. In other respects the arrange- I ment is the same as in Fig. 1.

Having now described my invention what I claim and desire to secure by Letters Patent of the United States is: i

1. In combination with an electric power and a driving motor electrically connected to the generator, of an exciter for the driving motor having three field windings one of which is shunted to the armature of the generator, the second .being connected in series to the armatures of the generator and the driving motor and-so arranged that it counteracts the first mentioned winding, whilet-he third winding'is connected to'the armature of the exciter itself,- substantially as and for the purpose set forth.

2. In an electrically propelled car the combination of, an electric generator for constant watts, a driving motor having two field windings one of which is connected to the armature of the motor and an excite-r connected to the second field winding of combination of, an electric generator for constant .watts, a driving motor, an ex citer for the latter having'three field windings, one of which islshunted to the arma-- ture of the generator, the second being connected in series to the armatures of thegenerator and the driving motor and so arranged that it counteracts the said shunt 'winding, while the third winding s connected t0.the armature of theexcite'ritself,

and a rheostat connected in, series to said shunt-winding, substantially as and for the P rpose set forth.

In testimony that. I claim the foregoing as my invention, I havesl'gned'my presence of two subscribing witnesses.

Witnesses:

A. Hosea, C. ABRAHAMBEN.

name in ERANS G. I'LILJENROTH. I 

